Now, research out of the University of Saskatchewan shows that food could be a vehicle for infections.

In a letter to appear in July in the U.S. Centers for Disease Control and Prevention’s journal Emerging Infectious Diseases, Dr. Joseph Rubin and his colleagues, Samantha Ekanayake and Champika Fernando, described finding a carbapenemase-producing Pseudomonas bacteria in squid purchased from a Chinese grocery store in Saskatoon, Canada.

The squid was tested in January 2014 as part of a drug-resistance surveillance pilot study, and, although there was no country-of-origin labeling on the product, the store owner said that, according to the distributor, the squid originated in South Korea.

“This is the first time that any carbapenemase has been identified in a food source,” Rubin told Food Safety News.

He added that it’s unknown if a carbapenem-resistant infection in humans has ultimately come from a food source, but the type of carbapenemase identified in the squid’s bacteria has previously been identified in a Salmonella entericaserotype from patients in France with a travel history to North Africa, suggesting possible foodborne transmission.

“A carbapenemase-producer has never been found in poultry or pork or beef,” Rubin said. “So this is something pretty new.”

There’s a lot that scientists still don’t know about the organisms, so there’s a lot of research that still needs to be done. The ecology of these organisms and of the resistance genes themselves was beyond the scope of this particular study.

“We don’t know for sure that it’s animal-driven,” Rubin said. “In this particular case, we really don’t have any information about when this organism would have entered the food chain.”

Did the squid acquire it from its environment, did it come from cross-contamination at processing, or was there something else?

A broader concern about carbapenemase-producing organisms is that, because bacteria can share DNA with each other, it’s possible that the resistance genes in a non-pathogenic or less-pathogenic species could transfer into one that’s more dangerous.

“This certainly is a very troubling finding,” Rubin said. “And, although we don’t yet know how widespread these organisms are in niche food products or how they got there, we certainly do need to expand our antimicrobial-resistance programs to address these questions.”

Carbapenemases are one of the biggest challenges regarding antibiotic resistance, he said, and it’s “a global problem that’s going to take a global effort.”